Yamaha V6 4.2 Liter Four-Strokes – Best Outboard Ever?

yamaha V6The Yamaha V6 outboards, covering from 225 to 300 horsepower, are some of the most popular powerplants on the market – and with good reason.

Whether you’re walking the docks at the Fort Lauderdale International Boat Show, walking the floor at the Fred Hall Show or just walking through a marina, you’ll notice that there are Yamaha V6 4.2L outboards all over the dang place. You’ll see 20-something center consoles with single F225s, bigger boats with twin F250s, and some bigger still with F300s. There engines are so prevalent it begs the question: Could the Yamaha V6 4.2 Liter four-strokes be the best outboard engines ever built?

yamaha V6
The Yamaha F250 is quite a familiar sight at boat shows, in marinas, and out on the water all across the nation.

Naturally, them’s fightin’ words. There are plenty of good things to say about the new Evinrude G2 outboards, and Mercury fans are uber-excited about the newly-introduced FourStroke outboard engine line.  Suzuki guys love their V6s too, and Honda owners often swear by their powerplants.

Yet one fact remains: the Yamaha V6 is shockingly popular because it’s a shockingly good motor.

Yamaha V6 Specifications

Let’s get the specs and details out of the way right up front. The three models are essentially the same, save for some computer mapping, alternator size (70 amps for the 300, 50 or 70 for the 250 or 225), and graphics. Weight is also very close between the models with the biggest variable being shaft length, ranging from 551 to 575 pounds. One important difference to note is that the F300 specs 89 octane fuel, while the F225 and 250 are fine with 87 octane. All are available with both digital and mechanical controls.

yamaha V6
There are very few significant differences between the motors; one perk of getting the F300 is that it’s available in white as well as the standard Yamaha silver we’re all so used to seeing.

Like Yamaha’s new V8 F425 XTO outboard, the V6 4.2L line maximizes displacement while minimizing weight in part with the use of plasma-fused sleeveless cylinder walls. In most outboards, since the aluminum alloy block can’t take the constant heat and friction of a piston’s nonstop banging, steel cylinder sleeves are needed. Unfortunately, the sleeves add weight while also reducing the inner diameter of the cylinder’s usable space. In this case, however, Yamaha coats the inside of the cylinders with a few thousandths of an inch of super-heated liquefied metals including a mix of chrome, nickel, magnesium, and “other elements” that are proprietary. When the process is complete, the cylinder walls are stronger than traditional steel sleeves to the tune of about 60-percent. In addition to cutting weight while boosting strength the plasma-fused cylinder walls are “micro-textured” with tiny dimples, which allows them to hold a minuscule amount of oil and thereby reduce friction between the cylinder and cylinder walls. Yamaha says this gets them a boost in both hole-shot, and mid-range acceleration.

Plasma-fused cylinder walls are dimpled in a similar fashion to the skin of a golf ball.

Other weight-saving measures taken on the V6 include a composite lower engine pan which saved over 10-pounds compared to an aluminum pan, utilizing plastic cam covers, reshaping the mid-section of the engine, and shifting to a lighter alternator. Taken together, the 4.2L is actually close to 20-pounds lighter than the 3.4L V6 it replaced almost a decade ago.

And what a decade it’s been. The 4.2L won an NMMA Innovation award when it was introduced, and Yamaha has won consecutive Customer Satisfaction Index (CSI) awards (requiring 90-percent or higher customer satisfaction) every year since the engine was introduced. In fact, Yamaha’s won the CSI award ever since its inception in 2001. That’s a testament to reliability, and we note that the 4.2L was one of the first outboard models to fail so rarely that people began comparing its dependability to that of a modern car.

Efficiency of the Yamaha 4.2L V6 Outboard

Yamaha claims “best in class” fuel efficiency for the 4.2L V6, specifying that at 3500 rpm they’re “up to 17 percent more fuel efficient than other four-stroke V6s.” But let’s be honest – there isn’t an outboard manufacturer on the face of the planet who isn’t able to make a similar claim by looking specifically at a cherry-picked rpm range, by dropping the “four-stroke V6” part of that assertion, or by making some other adjustment in the marketing pamphlet. That said, the 4.2L V6 is an extremely efficient motor, as demonstrated in many of Yamaha’s Performance Bulletins.

We’ve compared their bulletin numbers to those we’ve collected on our own dozens of times, and without fail, we’re always within a tenth or so of a gph or an mpg throughout the rpm range. So, we have no problem suggesting you use these bulletins to look at different types and sizes of fishing boats and rely upon them to get an idea of just how fuel burn will shake out with these engines on any specific boat you may own or consider buying.

Other points to consider: the Yamaha V6 is amazingly quiet, with the loudest sound at idle being the stream of the tell-tail hitting the water. Yamaha also gets extra points for its SDS system, available in props designed for use with the V6 line, which utilizes a soft rubber hub to cushion shifting and eliminate much of the “clunk” you (and possibly the fish) normally hear and feel when going into forward or reverse.

The Yamaha V6s are pleasant to run when compared to many outboards, thanks to their quiet disposition and the SDS propellers they can swing.

Bottom Line on the Yamaha V6 4.2L Outboard

In many cases, you may be able to take an engine from one of Yamaha’s competitors and make a factual argument as to why it could be “better” than the 4.2L V6. But it’s just as reasonable to argue for the Yamaha in each and every case. To some degree there’s an esoteric aspect to determining one outboard’s superiority to another, and that’s before brand loyalty and emotion even enter the debate. The bottom line? You certainly don’t have to call the Yamaha 4.2L V6 four strokes the best outboard engines ever built – but there’s a very strong argument for doing just that.

Visit Yamaha outboards, if you want to look into the V6 or any of their other engines.

Lenny Rudow …has been a writer and editor in the marine field for over two decades, and has authored seven books. He is currently the Angler in Chief at Rudow's FishTalk Magazine, is Electronics and Fishing Editor for BoatUS Magazine, and is a contributing editor to several other publications. His...